U.S. patent application number 15/577732 was filed with the patent office on 2018-05-10 for electronic angle measuring device for a bending machine for measuring the bending angle between the limbs of a sheet.
The applicant listed for this patent is KEBA AG. Invention is credited to Andreas Wogerbauer, Johann Wogerbauer.
Application Number | 20180128604 15/577732 |
Document ID | / |
Family ID | 56119241 |
Filed Date | 2018-05-10 |
United States Patent
Application |
20180128604 |
Kind Code |
A1 |
Wogerbauer; Johann ; et
al. |
May 10, 2018 |
ELECTRONIC ANGLE MEASURING DEVICE FOR A BENDING MACHINE FOR
MEASURING THE BENDING ANGLE BETWEEN THE LIMBS OF A SHEET
Abstract
An electronic angle measuring device for a bending machine for
measuring the bending angle between the legs (4) of a sheet (5)
using a sensor element (7) is described, which supplies
angle-equivalent signals in a contactless manner to a signal
processing unit (9), which has a microprocessor and a memory unit
and is connected to a digital display (10). To provide simple
measuring conditions, it is proposed that the sensor element (7),
the signal processing unit (9), and the display (10) form an angle
measuring device (6) which is fastenable on the upper tool (1) of
the bending machine and is usable as a handheld encoder, and which
has a motion sensor (11), which is connected to the signal
processing unit (9) and detects the lowering and/or raising
movement of the upper tool (1), for triggering the measuring
procedure
Inventors: |
Wogerbauer; Johann; (Linz,
AT) ; Wogerbauer; Andreas; (Linz, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KEBA AG |
Linz |
|
AT |
|
|
Family ID: |
56119241 |
Appl. No.: |
15/577732 |
Filed: |
May 25, 2016 |
PCT Filed: |
May 25, 2016 |
PCT NO: |
PCT/AT2016/050163 |
371 Date: |
November 28, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01B 2210/58 20130101;
G01B 21/22 20130101; G01B 11/26 20130101; B21D 5/0272 20130101;
B21C 51/00 20130101; B21D 5/006 20130101; B21D 5/02 20130101; G01B
21/047 20130101 |
International
Class: |
G01B 11/26 20060101
G01B011/26; G01B 21/22 20060101 G01B021/22; G01B 21/04 20060101
G01B021/04; B21D 5/02 20060101 B21D005/02; B21D 5/00 20060101
B21D005/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2015 |
AT |
A 334/2015 |
Claims
1. An electronic angle measuring device for a bending machine for
measuring bending angle between legs of a sheet said device
comprising: a sensor element that supplies angle-equivalent signals
in a contactless manner to a signal processing unit, which has a
microprocessor and a memory unit and is connected to a digital
display, wherein the sensor element, the signal processing unit,
and the display form said angle measuring device, which is
fastenable on an upper tool of the bending machine and is
configured to be used as a handheld encoder, and which has a motion
sensor that is connected to the signal processing unit and detects
a lowering and/or raising movement of the upper tool, so as to
trigger a measuring procedure.
2. The electronic angle measuring device according to claim 1,
wherein the motion sensor is configured as a multi-axis
accelerometer.
3. The electronic angle measuring device according to claim 2,
wherein the signal processing unit corrects a signal of the
accelerometer by a signal component based on the acceleration of
gravity.
4. The electronic angle measuring device according to claim 1,
wherein the device has a housing that has at least one permanent
magnet in rear wall thereof adapted to fasten on the upper
tool.
5. The electronic angle measuring device according to claim 1,
wherein the signal processing unit has a radio interface.
6. The electronic angle measuring device according to claim 1,
wherein the signal processing unit signals overshooting or
undershooting of programmable tolerance limits of an angle to be
measured.
7. The electronic angle measuring device according to claim 1,
wherein the signal processing unit analyzes measured values, which
are stored in the memory unit during the lowering and raising
movement of the upper tool, according to mathematical methods to
increase accuracy of the measured values.
8. The electronic angle measuring device according to claim 1,
wherein the sensor element has a rotating mirror deflecting a laser
beam onto the two legs of the sheet and forms a measured value from
the reflected beam received in an emission direction.
Description
FIELD OF THE INVENTION
[0001] The invention relates to an electronic angle measuring
device for a bending machine for measuring the bending angle
between the legs of a sheet using a sensor element, which supplies
angle-equivalent signals in a contactless manner to a signal
processing unit, which has a microprocessor and a memory unit, and
which is connected to a digital display.
DESCRIPTION OF THE PRIOR ART
[0002] The measurement of the bending angle in sheet bending is of
substantial significance, since the workpiece rebounds after the
bending process depending on the material, the thickness of the
sheet, the rolling direction, and the like. With the use of an
effective measuring device, the bending result can therefore be
monitored while still in the machine and/or corrected and/or
improved by a manual or automatic rebending procedure, without the
workpiece having to be removed from the machine. This means that
the angle measurements are to be carried out depending on the
lowering and raising movement of the upper tool, which requires a
control of the measuring device adapted to the control of the
bending machine. The integration of such known measuring devices
into a bending machine and the machine-dependent control thereof
requires a complex adaptation of the bending machines by special
designs, however.
[0003] For the contactless measurement of the bending angle between
the legs of a sheet to be bent in a bending machine, measuring
devices are known (DE 43 12 565 C2), which are based on a light
intersection method. In addition, however, using measuring devices
(JP 2002-59217 A) in which the circumstance is utilized that the
radiation intensity of a laser beam reflected on a leg of the sheet
and received in the emission direction is greatest when the laser
beam is incident perpendicularly on the sheet leg is also known.
For this purpose, a mirror is provided in the region of the upper
tool of the bending machine, which rotates about an axis parallel
to the vertex axis of the bending angle and is inclined at
45.degree. in relation to this rotational axis, so that a laser
beam incident on the mirror in the direction of the rotational axis
is deflected in a plane perpendicular to the rotational axis on the
leg of the sheet to be bent and is reflected by the legs,
specifically in the emission direction if the laser beam is
perpendicular to the respective leg. The respective angle between
the two legs can then be ascertained in a signal processing unit
via the associated rotational position of the drive motor for the
mirror. The disadvantage for the use of such a measuring device, of
having to adapt the design of the bending machine, remains,
however.
SUMMARY OF THE INVENTION
[0004] The invention is therefore based on the object of providing
simple structural conditions to be able to equip, even by
retrofitting, a bending machine with an electronic angle measuring
device for measuring the bending angle between the legs of a sheet,
without having to perform complex refitting measures on the bending
machine.
[0005] The invention achieves the stated object by way of the
features of claim 1.
[0006] Since the measuring device is designed as an angle measuring
device, which comprises the units necessary for the angle
measurement, namely a sensor element, which supplies
angle-equivalent signals in a contactless manner to a signal
processing unit, which has a microprocessor and a memory unit, is
connected to a digital display, and is also arranged in the angle
measuring device, this angle measuring device only has to be
fastened to the upper tool of the bending machine, which does not
require complex design refitting of the bending machine. The upper
tools of the bending machines are typically assembled from
individual stamp segments, which interact with a matrix-like lower
tool. For measuring access to the two legs of the sheet to be bent,
it is therefore merely necessary to leave a measuring gap free
between two stamp segments and to align the angle measuring device
in relation to this measuring gap.
[0007] Since the angle measuring device has a motion sensor, which
is connected to the signal processing unit and detects the lowering
and/or raising movement of the upper tool, for triggering the
measuring procedure, the angle measuring device can be operated
independently of the machine controller. The movement of the upper
tool is detected by the angle measuring device itself by way of the
motion sensor, so that angle measurements can be carried out
automatically in synchronization with the work cycles of the
bending machine, without special provisions having to be taken for
this purpose on the bending machine, for example, providing cables
or interfaces to the machine controller for the exchange of
synchronization signals. This applies to the use of the angle
measuring device both as a machine encoder and also as a handheld
encoder.
[0008] Particularly advantageous design conditions result if the
motion sensor is designed as a multi-axis accelerometer, because in
this case a simple alignment of the angle measuring device in
relation to the vertex axis of the bending angle, which typically
extends horizontally, is possible with the aid of the multi-axis
accelerometer. The detection of the direction of gravity on the
basis of an analysis of the acceleration signals by the signal
processing unit can additionally be used for inclination detection
and display of the inclination angle.
[0009] The detection of the acceleration of gravity by the
multi-axis accelerometer additionally enables a correction of the
signal of the accelerometer by the signal component based on the
acceleration of gravity, so that exclusively motion changes of the
angle measuring device and therefore the upper tool are detected.
The velocity and the travel of the upper tool for the start and the
end of the measuring procedure may therefore be ascertained from
the corrected, offset-free acceleration values.
[0010] In relation to the direct analysis of the signal of the
acceleration sensor, which is proportional to the acceleration, the
use of the value of the velocity derived therefrom or of the
distance traveled is advantageous because if the acceleration is
merely observed, incorrect triggering can occur, as a result of
strong shocks, as can occur on industrial bending machines. Vice
versa, for example, in the case of electrically operated bending
machines, the motion can be initiated with low acceleration, so
that a threshold value which is merely established for the
acceleration is not exceeded at all and therefore also no measuring
procedure would be triggered. In the case of bending machines,
however, at least during the displacement of the upper tool from
the base position into the working position and during the
resetting into the base position after the bending procedure, a
sufficiently high velocity occurs to be able to synchronize the
measuring and bending procedures reliably. It is to be noted in
this context that angle measurements can advantageously be carried
out when the bending procedure is completed or nearly completed,
i.e., before or at the beginning of the raising movement of the
upper tool.
[0011] The signal of the accelerometer can also be used to activate
essential parts of the angle measuring device, in particular the
sensor element, the display, and/or the microprocessor and/or to
switch them from an energy saving rest mode into an active
operating mode. The time of the power consumption is thus
substantially reduced to the short movement phases of the upper
tool in which the bending angle can actually be measured, whereby
the required battery or rechargeable battery capacity and,
accompanying this, the structural size of the angle measuring
device can be reduced.
[0012] However, with the aid of the accelerometer, the angle
measuring device can also be switched over between a machine use
and a handheld use. The fixed location of the angle measuring
device, which is unchanged on the upper tool, is easily
differentiable from use in the case of manual guiding by means of
the acceleration sensor. The handling is simplified and the risk of
incorrect operation is reduced with the automatic switching
over.
[0013] So as not have to perform any additional measures for
fastening the angle measuring device on the bending machine, the
device housing can have a permanent magnet in its rear wall for
fastening on the upper tool, which not only provides advantageous
installation conditions, but rather is also accompanied by the
option of simple readjustment of the angle measuring device with
respect to the vertex axis of the bending angle and the measuring
gap.
[0014] If the signal processing unit has a radio interface, any
cables are thus dispensed with, to be able to read out data of the
angle measuring device and specify it to the machine controller,
for example, or to be able to access the angle measuring device in
a controlling manner from the outside. In this context, it probably
does not have to be especially emphasized that batteries or
rechargeable batteries suggest themselves for the power supply, to
avoid cable terminals.
[0015] If the signal processing unit signals overshooting or
undershooting programmable tolerance limits of the angles to be
measured, it is thus advantageously possible to intervene in the
bending procedure to ensure tolerance limits are maintained.
[0016] To improve the measured value accuracy, in particular during
the raising movement of the upper tool, measured values can be
stored in the memory unit, so that these measured values can be
analyzed according to mathematical methods by the signal processing
unit to increase the measured value accuracy. In particular
reverberation procedures can thus be detected and the associated
measured values can be eliminated. Furthermore, the analysis of a
plurality of measured values enables a plausibility check of the
measurement result and a judgment of the quality and/or the
reliability of the displayed measured value.
[0017] A comparatively simple structure of the angle measuring
device is achieved in that the sensor element has a rotating mirror
for deflecting a laser beam onto the two legs of the sheet and
forms a measured value from the reflected beam received in the
emission direction. For this purpose, the angle measuring device
has a laser emitter for a laser beam, a continuously revolving
mirror, which is arranged between the two legs of the sheet, and is
axially-parallel to the vertex axis of the bending angle, having an
emission direction perpendicular to the rotational axis for the
laser beam, a receiver for the laser beam reflected in the emission
direction on the legs, and a signal processing unit connected to
the receiver. The laser beam, which is deflected perpendicularly to
the rotational axis of the mirror onto the legs of the sheet,
passes in this case through a measuring gap of the upper tool. This
is not only accompanied by simple design conditions, but rather
also makes the measurement independent of the location of the angle
measuring device on the upper tool.
BRIEF DESCRIPTION OF THE DRAWING
[0018] The subject matter of the invention is illustrated by way of
example in the drawings. In the figures
[0019] FIG. 1 shows a bending machine having a digital angle
measuring device according to the invention in a partially cutaway,
schematic side view
[0020] FIG. 2 shows this bending machine in a schematic vertical
section, and
[0021] FIG. 3 shows the electronic angle measuring device according
to the invention in a simplified block diagram.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] The illustrated bending machine has an upper tool 1, which
can be lowered and raised, and which interacts with a lower tool 2
in the form of a matrix and is assembled from stamp segments 3
arranged next to one another. A digital angle measuring device 6,
which comprises a sensor element 7 having a mirror, which is
rotated about a rotational axis parallel to the vertex axis of the
bending angle between the two legs 4 of the sheet and deflects a
laser beam in a plane perpendicular to the vertex axis onto the two
legs 4, is fastened onto the upper tool 1 for measuring the bending
angle between the legs 4 of a sheet 5 to be bent. The laser beam
passes in this case through a measuring gap 8 between two stamp
segments 3. Since the sensor element 7 has a receiver for the laser
beam reflected in the emission direction on the legs 4 and the
intensity of the reflected laser beam is greatest when the laser
beam is perpendicular to the legs 4, the rotational position of the
mirror can be specified for the laser beams which are perpendicular
to the legs 4 of the sheet 5, as indicated in FIG. 2. Therefore,
the respective bending angle between the two legs 4 may be derived
from these rotational positions of the mirror.
[0023] For this purpose, according to FIG. 3, the sensor element 7
is connected to a signal processing unit 9, which analyzes the
measurement signals received from the sensor element 7 and outputs
the measured bending angle at a display 10. This display 10 is
required not only for the use of the angle measuring device as a
handheld device, but rather also enables the bending angle and
other displayed data to be read off during use as a machine
encoder, without having to turn away the view decisively from the
sheet 5, which is anyway located in the field of vision.
[0024] Since the angle measuring device 6 has a motion sensor 11
connected to the signal processing unit 9, the angle measurement
can be synchronized with the motion of the upper tool 1 via the
detection of the motion of the upper tool 1, without having to make
use of the machine controller. The electronic angle measuring
device 6 can therefore be used without complex refitting work in
existing bending machines if a measuring access of the sensor
element 7 to the two legs 4 of the sheet 5 is possible, which can
be ensured in a simple manner in the case of the typical assembly
of the upper tool 1 from stamp segments 3. The angle measuring
device 6 is solely to be fastened accordingly on the upper tool 1.
For this purpose, providing at least one permanent magnet 12 in the
region of the housing rear wall of the angle measuring device 6
suggests itself.
[0025] If the motion sensor 11 is designed as a multi-axis
accelerometer, by means of its signals for the acceleration of
gravity, the angle measuring device 6 can be aligned in a simple
manner in relation to the horizontal vertex axis of the bending
angle between the two legs 4, which is predefined by the matrix and
the stamp segments 3. In addition, it is possible to analyze a
measurement signal corrected with respect to the acceleration of
gravity, so that exclusively accelerations of the angle measuring
device 6 can be used for ascertaining the motion of the upper tool
1.
[0026] Storing measured values during the raising movement of the
upper tool 1 is particularly advantageous for the formation of
accurate measurement results. By way of measurements also during
the rebound of the sheet 5 after the bending procedure,
reverberation procedures can be eliminated by the signal processing
unit 9 with the aid of suitable mathematical methods and the final
result can be improved. The measuring procedure is preferably ended
by a microprocessor, which computes an end of the bending procedure
on the basis of an analysis of the measured value family.
Alternatively, ending the measuring procedure after passage of a
fixed time span or after traveling a certain distance of the upper
tool ascertained from the signal of the motion sensor is also
possible.
[0027] If the angle measuring device 6 has a radio interface 13,
data can thus not only be transmitted wirelessly from the angle
measuring device 6 outward, but rather also data can be transmitted
from the outside to the angle measuring device 6. To be able to set
different operating modes for the angle measuring device 6, the
angle measuring device can additionally be provided with an input
14. To be freed of cable terminals, the angle measuring device 6 is
preferably to be equipped with batteries or rechargeable batteries
15 for the power supply.
* * * * *